The present invention relates to a ski binding with device for compensating the calibration load for toe unit safety release.
As is known, the ski may flex while skiing, due to the presence of holes or of other discontinuities in the ski-run, as a consequence of the central load constituted by the weight of the skier.
In known bindings, such as for example in the binding illustrated in the U.S. Pat. No. 3,920,256, there is a spring which allows to keep the axial distance between the toe unit and the heel unit constant during the flexing of the ski. This spring, which is commonly termed elastic recovery spring, opposes the rearward motion of the heel unit during the flexing of the ski, which allows to keep the axial distance constant. The load imparted to the elastic recovery spring in practice constitutes an increase in the pressure of the toe unit on the tip of the boot, which consequently increases the value of the preset limit load for the release calibration; this increase has been experimentally found to be approximately equal to 20%.
Increasing the limit load in practice reduces safety, since safety release will be activated at a load threshold higher than the preselected one, since the load which acts at the ends of the boot has increased.
A previous binding of the same applicant instead uses a lamina which interconnects the toe unit and the heel unit below the sole of the boot; the means for calibrating the toe unit release means are accommodated in said heel unit.
With this type of binding, the flexing of the ski would cause a slackening of the calibration means, since the lamina is linked to the axial distance and accordingly, in case of ski flexing, said lamina would move rearward and reduce the calibration load of the spring, which despite being arranged in the heel unit controls the automatic release of the toe unit.